Mattress foundation



FIG. 1 is a left side, top perspective view of a mattress foundation embodying my design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a left side view thereof, the right side being a mirror image thereof;

FIG. 4 is a foot end view thereof, the head end being a mirror image thereof;

FIG. 5 is a top plan view thereof in its intended environment;

FIG. 6 is an enlarged perspective view taken from FIG. 1 showing a portion of the mattress foundation; and,

FIG. 7 is an enlarged side view taken from FIG. 3 showing a portion of the mattress foundation.

The broken lines in FIGS. 1, 3, 4 and 5 showing a mattress illustrates environment and form no part of the claimed design. The broken lines showing the boundaries of the enlarged detailed views in FIGS. 6 and 7 form no part of the claimed design. 

CLAIM I claim the ornamental design for a mattress foundation, as shown and described. 